This research program will investigate the effects of hormones, particularly insulin, catecholamines, dibutyryl cyclic AMP and methyl xanthines on the levels of functional (endothelial) lipoprotein lipase in isolated perfused rat heart and epididymal adipose tissues. It will determine changes in functional levels induced in streptozotozin-diabetes. Finally, differences in response to lipase in these tissues to the lipid composition of triglyceride-rich lipoprotein substrates will be determined. It is anticipated that the results obtained will provide the first information on the effects of physiological levels of hormone and other effectors, delivered via the vascular route, on triglyceride catabolism by these tissues.